Caulking gun with means to prevent rotation of compound cartridge during use and to provide positive pressure release

Abstract

A caulking gun adapted to receive a tube-like cartridge of compound, wherein the cartridge has a piston in one end which expels compound from a dispensing nozzle as the piston is moved forward in the cartridge towards the dispensing nozzle. The gun includes a cartridge holder, a handle attached to the cartridge holder, and a trigger cooperating with the handle to urge a stem fixed against rotational movement relative to said cartridge holder and a disk fixed on the stem against rotational movement relative to the stem against the piston of the cartridge to expel compound from the discharge nozzle. One outwardly projecting prong is eccentrically positioned on the disk in contact relation with the piston of the cartridge for wedging into the contact surface of the piston without puncturing through the piston into the cartridge, whereby compound is prevented from leaking. The prong engages the piston to prevent rotation of the cartridge as compound is expelled in order to maintain the angle of articulation and to exert a positive pull on the piston and urge it rearwardly away from the dispensing nozzle as the stem is retracted from contact with the piston and before disengaging completely from the piston. This releases pressure on the piston and stops the flow of compound from the dispensing nozzle.

We claim: 
     
       1. In a caulking gun of the type adapted to receive a tube-like cartridge of compound, wherein the cartridge has a piston in one end which expels compound from a dispensing nozzle as the piston is moved forward in the cartridge towards the dispensing nozzle, the gun having a cartridge holder, a handle attached to the cartridge holder, and trigger means cooperating with the handle to progressively urge a stem fixed against rotational movement relative to said cartridge holder and a disk fixed on the stem against rotational movement relative to the stem against the piston of the cartridge to expel compound from the discharge nozzle, the improvement which comprises at least one outwardly projecting prong eccentrically positioned on the disk in contact relation with the piston of the cartridge for wedging into the contact surface of the piston in non-undercutting relation to the piston without puncturing through the piston into the cartridge whereby compound is prevented from leaking therefrom, said prong engaging said piston to prevent clockwise or counterclockwise rotation of the cartridge as compound is expelled in order to maintain the angle of articulation of an angularly-cut dispensing nozzle and to exert a positive pull on the piston to urge it slightly rearwardly away from the dispensing nozzle as the stem is retracted from contact with the piston and before disengaging completely from the piston in order to release pressure on the piston and stop the flow of compound from the dispensing nozzle. 
     
     
       2. In a caulking gun according to claim 1, wherein said prong comprises an integral portion of said disk punched from and bent outwardly from the disk. 
     
     
       3. In a caulking gun according to claim 1 or 2, wherein the disk includes at least two prongs formed in spaced-apart relation on the disk for contacting the piston at two spaced-apart points. 
     
     
       4. In a caulking gun according to claim 3, wherein said stem comprises a polygonal shape in cross-section, and wherein said gun includes a latch dog carried on the cartridge holder adjacent the handle, the latch dog having a hole with a shape mated with the shape of the stem to receive the stem and prevent rotation thereof. 
     
     
       5. In a caulking gun according to claim 1, wherein the disk is releasably attached to the stem.